The rapid growth of the Open Government Partnership (OGP) over the past year has demonstrated that dialogue and cooperation can result in concrete commitments to build responsive and accountable institutions.

Since its September 2011 launch by eight governments (including the United States) and nine civil society organisations, 55 countries have committed to taking steps towards openness through OGP. Today, what was once an idea is now a tangible and growing community encompassing one quarter of the world's population.

As part of their commitments under OGP, these 55 governments have pledged to develop and implement outcome-orientated national action plans. The action plans establish – for the first time, in some cases – public accountability mechanisms, accessible and usable open data portals, transparency in natural resource management, and processes for citizen budgeting, among other goals.

However, as US secretary of state Hillary Clinton remarked at the inaugural OGP in Brasilia in April, "it is not enough to assert that we are committed to openness … we have to deliver on the commitments that we have made." The true measure of OGP's success is not the height of our aspirations, but the depth and breadth of our action.

OGP is already creating a "race to the top" in good governance, with citizens articulating the terms of success. But our triumph will play out in the coming year, as participating governments, together with civil society and private sector partners, begin to implement their action plans – with each commitment ultimately impacting people's lives.

When US president Barack Obama first challenged nations to recommit to transparency, accountability, and citizen participation in September 2011, few could have imagined the international momentum that would result. Clinton said, in Brasilia, the US is proud to be the founding chair of this unprecedented initiative, "and we intend to do all we can to help make the Open Government Partnership a leader in ensuring that the 21st century is an era of openness, transparency, accountability, freedom, democracy, and results for people everywhere."

The US looks forward to supporting the new chairs of OGP – the UK, Brazil and the International Budget Partnership – as we advance openness as the new standard for good governance around the world.

María Otero is the US under secretary of state for civilian security, democracy, and human rights. On behalf of the US, she served as the founding co-chair of the Open Government Partnership.